Have you looked at the Music Composition major within the College of Creative Studies at UCSB? https://ccs.ucsb.edu/sites/default/files/2019-10/curriculum-guidelines-corr-2019-20_1.pdf The CCS application (in addition to the regular UC application) requires a Letter of Intent, a portfolio (“work in evidence of talent”), and at least two letters of recommendation.
URochester might be another school to look at. In addition to the BA in Music http://www.sas.rochester.edu/mur/undergraduate/requirements.html (and the conservatory programs at Eastman), there’s a Music Cognition track in the department of Brain & Cognitive Sciences http://www.sas.rochester.edu/bcs/undergraduate/tracks.html#mc and and Audio and Music Engineering program. http://www.hajim.rochester.edu/ame/